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Crumpp's algebra doesn't change the equation except to clean it up and make it clearer. (T-D)/W = T/W - D/W --- BOTH are divided by weight either way you look at it. When you divide DRAG by WEIGHT you have already included the resisting inertia, that's what the freaking division there is about! Saying THEREBY it is less powerful at resisting inertia is a fallacy, unreal and leading to unreal expectation. ADDED: The WHOLE equation, EITHER WAY, includes drag divided by weight resisting thrust also divided by weight -- it doesn't matter if they are divided by weight and one subtracted by the other or if they are subtracted and the result divided by weight, the answer is the SAME. More important: that answer ALREADY contains your "thereby"'s, any further 'application' of those is BS so just quit trying to get 'extra mileage' out of it! (END ADDING) The equation EITHER WAY includes the effect of THRUST also divided by WEIGHT and scaled the same as DRAG. The whole is in the equation, done deal and NOT subject to some after-equation re-application of the same elements with (possibly) lift force thrown in for smoke.
Who ignored division of drag by weight? Crumpp did not. But then unlike YOU he does not ignore the rest of the relation but treats it as a whole, without adding extra parts that simply are not there even in speculation. If someone presents half a page of BS that's dependent on a few wrong points then to address those points is not "losing the meaning". It's putting a stop to meaning being taken off for a long walk on a short pier. "My views are solely my own and do not reflect the views of my Squad or its members" |
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What is the standard aerodynamic procedure you refer to above? Calculating aircraft performance at 0 Km and using that to predict acceleration at 7 Km?  Or are you saying that the calculation you made above does not represent flying conditions at 0 Km 400 Km/h TAS but actually represents flying conditions at 400 Km/h TAS at 7 Km and that you have used 215 KEAS (Knots equivalent airspeed?) in the equation above to achieve this? What Cdo and e (Oswald factor) do you assume for the Spitfire and Fw190 respectively? |
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So does that mean that in your opinion, that while the power changes with altitude for both aircraft, that the relative power you have used in your equation will be the same, i.e 1419.5/1296=1.095 for both 0 and 7 Km or what do you mean? This message has been edited. Last edited by: Holtzauge, |
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The horizontal acceleration numbers I get in my simulation at 400 Km/h TAS 7 Km are: Fw 190 A3: 0.90 m/s*2 Spitfire Mk 9: 1.22 m/s*2 So that is pretty close for the Fw190. What do you get for the Spitfire FC? |
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Holtzauge, EAS is standard if you are going to compare aircraft as it puts the aircraft in the same condition of flight regardless of atmospheric properties. If you take a TAS speed then you also accept whatever atmospheric model that speed was determined in. EAS calculations will yield good relative performance, convenient to use, and much more versatile. The acceleration picture is not going to change in a dive. The Focke Wulf will out accelerate the Spitfire when a component of weight shifts to thrust.   If you want specific performance then the conversion to TAS is quite simple. Since your using the same onset and atmospheric model, you eliminate those differences that are found in directly transferring source data. Density effects are universal. It is a property of the atmosphere the aircraft are flying in and not the airplanes. At the same altitude, both aircraft will be effected exactly the same. All the best, Crumpp If I can't advertise for my Museum. Then there is no point in posting on these forums. |
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You keep bringing up horizontal acceleration. However you fail to address your erroneous claim for dive acceleration.
All the best, Crumpp If I can't advertise for my Museum. Then there is no point in posting on these forums. |
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The TWO only places I can see in that formula that a difference would be made are:
1) Engine power differences at 7km would have to be very different than at 0km. 2) In one example we have a FW-190A-3 and in the IL2 example we have a de-rated FW-190A-4. IOW, apples and oranges time again and people taking positions without regarding the fact. "My views are solely my own and do not reflect the views of my Squad or its members" |
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I don't have data for Spit on my PC, I basically gave up on Spits, there is so many different variants and test results that you can find one for any agenda you might have. As our results for FW are similar and difference is most likely due to input numbers I don't have any reason to doubt your results for Spit if input numbers are correct. Il2 is good game and calculations from the game shows same trend as your calculation. If I take one of the LF SpitV I'm sure that situation will be completely different with FW dominating in dive accel in whole speed range.
1. And they are. Also keep in mind that 400Kmh TAS is medium speed at SL but very slow at 7000m AoA and Drag changes. 2. Derated A4 is not that different, compare it to values calculated for A3. ----------- People forgetting that Gravity works for lighter plane too and that difference between planes is not that big. At 7000m and 400Kmh TAS some Spit variants are significantly better than FW190A4 and weight difference is not big enough to compensate the lack of excess power. Another important thing is that these calculations are made with "perfect" engines that can go from low power to max power instantly. In RL that's not the case. Faster response to throttle changes, better dive entry etc. all of that contribute to RL results and all of that have to be taken into account when conclusions are made. This is extremely important in simulations. How to express with equations excellent cockpit design and ergonomic in FW which played big role in it's RL success? Should plane get some unrealistic performance boost to compensate for this? It seems to me that some players expect that. FC |
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If you read what you quoted you will find that it is stated that EAS is useful to compare two aircraft flying at DIFFERENT altitudes. Right now we have BOTH planes at 7 km so let's stay there. But by all means, if you want to use EAS then fine. Then perhaps you can enlighten us as to how you used EAS in the calculation you did. That bring us back to the questions I put in my post above which you still have not answered: Are you saying that the calculation you made above does not represent flying conditions at 0 Km 400 Km/h TAS but actually represents flying conditions at 400 Km/h TAS at 7 Km and that you have used 215 KEAS (Knots equivalent airspeed?) in the equation above to achieve this? What Cdo and e (Oswald factor) do you assume for the Spitfire and Fw190 respectively? PS: And thanks for bringing to our attention that density effects are universal. I'm sure the forum was very relieved to hear that. |
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And you keep on not understanding, so I'll explain why it is sufficient to look at horizontal acceleration only with the simple formula that you yourself use above: F=m*a=T-D+sin(20)*m*g dividing by m to obtain accceleration: a= (T-D + sin(20)*m*g)/m So this is what you use but we can also rearrange it like this: a=(T-D)/m +sin(20)*g Now notice that the second part is not dependant on mass but on angle only and this contribution is exactly the same for both aircraft and so it is irrelevant in this case where we disagree on which of the planes accelerates the better. So this leads to the conclusion that whichever plane has the largest (T-D)/m will accelerate the better. But (T-D)/m is also known as the horizontal acceleration. Q.E.D And PS: In the C++ simualtion, I do factor in the dive angle. In fact I factor in a lot more as I explained before when I confirmed that I use a formula similar to the one M_Gunz posted earlier. You need to improve your reading and/or memory skills. |
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I'm still waiting on an answer to this. The power of the aircraft is crucial to the analysis so why do you avoid to answer Kettenhunde? |
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I did not even realize your game FW190 was de-rated. Certainly remove a couple of hundred thrust horsepower from the FW-190's thrust picture and things change.
Wow! No wonder you are up in arms. My analysis and conclusions is based on 400kph EAS and 600kph EAS at the BMW801's 1st Gear FTH. I am so used to seeing EAS that it did not register you would be using anything else. We are nowhere near the same condition of flight. On the backside of the power curve, the Spitfire has the acceleration advantage at all altitudes just as the FW-190 has the advantage on the front side where it has the speed advantage. 400kph at 7Km is 171mph TAS at 0Km, HUGE difference in the condition of flight. We are talking at cross purposes. Thanks, M_Gunz for realizing that. 400kph EAS at 0km is the exact same speed as 400kph EAS at 7Km. That is why we use it. I don't have to convert from TAS to EAS and then Back to TAS for find out the speed at altitude. Using EAS I can easily determine the TAS for any altitude. I can also compare aerodynamic characteristic without any conversion hassles. The final EAS can very easily be converted to TAS if I wish. TAS mainly used for navigational planning. EAS is not used for just different altitudes. It is used whenever we want to examine aircraft performance because it eliminates altitude conversions. For example: You read an TAS speed form a WWII aircraft from country B that says 450mph TAS at 23000 feet. Country A's airplane travels 440mph TAS at 23000 feet. Country B because of atmospheric modeling uses a SMOE of 1.44 at 23000 feet so our 450mph TAS = 312.5 EAS Country A because of atmospheric modeling uses a SMOE of 1.408 = 312.5 EAS Both aircraft travel at exactly the same speed! The only difference is the value of TAS on paper. In the air these planes really both travel at exactly the same speed. See why we use EAS? If we were to use TAS 60 years later without the correct atmospheric modeling, our aerodynamic data is going to be wrong. It did not dawn on me that you guys would be mucking around with TAS in comparing aircraft. For my part in the confusion I apologize, Holtzauge. All the best, Crumpp If I can't advertise for my Museum. Then there is no point in posting on these forums. |
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http://womanpilot.com/?p=61 Just by varying the power, you can determine the performance at any altitude and have all the correct aerodynamic data. All the best, Crumpp If I can't advertise for my Museum. Then there is no point in posting on these forums. |
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Somehow I had thought that the AFDU tests used IAS, 400kph being a realistic combat speed
at least after maneuvers begin and 600-700kph being more the pre-turn and BnZ speed. I had also seen so many posts before moaning about the IL2 A-4 not being all it, uhhh, should with the, IIRC 1.3ATA instead of 1.42ATA. From Oleg; we should use the A-5 instead. Is this thread going where? We have formulae that can be used in dive and zoom, just not agreeing on numbers and outcomes. We -can- get back on track maybe? The algebra you are both using is equivalent but the values being plugged in are not. If you dismiss and don't look then no way to work this out. EDIT: perhaps if I didn't take so long finding the words......... Crumpp DID write 215KEAS and I *think* that 215K is for knots. "My views are solely my own and do not reflect the views of my Squad or its members" |
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Excuse me please, To whom is the schooling above directed? Is the schooling above directed at someone who is not aware of the facts concerning the math, the symbols, what Crumpp did or did not do, or is there no one in particular targeted with that effort to restate and repeat what has already been written more than once? A specific person being targeted by those repetitions could narrow down the possible people to which those words are directed toward. For my part I’ve already acknowledged the math, and symbols, and what Crumpp did do as Crumpp rearranged the focus away from illustrating drag loading and toward something other than drag-loading.
Here again is a case of miss-something. If the person targeted for refutation or whatever is being done with that example above can be identified and the words being refuted can be identified, then a quote can suffice to exemplify exactly (rather than ambiguously or inaccurately) what is being refuted or referenced in any way, shape, or form Example:
Who is “Saying THEREBY it is less powerful at resisting inertia…” and in what context is that person saying those words – exactly? An assumption could be made, guilt by association perhaps, where someone who said something similar to the above is now guilty of saying the above, in or out of context, and such an assumption would fail to be accurate without the actual quotes, in or out, of context. A simple illustration can show how drag loading does work: Applet Increase mass and what happens? D/W: where W increases while D remains the same. (D/W)V: where W increases while D remains the same and V remains the same. The power to resists motion is divided by the weight which causes less deceleration and the cannon ball goes farther even while the starting velocity remains the same. That is the context by which someone, me, made the statements that may, or may not have, inspired the reply as such:
Ps (negative acceleration) = (D/W)V: where no engine power adds a positive acceleration force. Ps = [No T/W – D/W]V: where engines are not producing any thrust such as when a vertical zoom climb (no induced drag to account for) is performed side by side with a P-47 and a Spitfire and the lack of lift force, and the lack of thrust force, illustrates drag loading only, separate, and disconnected from lift and thrust force to see the effect of drag-loading. See how my words convey my thoughts and how the Straw-Man can only speak for the creator of the Straw-Man. How quoting my words would be ridiculous when the idea is to create a Straw-Man? The applet illustrates the concept of Drag-Loading. Words illustrate the concept of Drag-Loading. Drag-Loading doesn’t require Straw-Men to make Drag-Loading real in reality. D/W is just three symbols. Another Applet That applet works on Mozilla FireFox for me and does not work on IE for me. It is less cluttered than the other one. So…next time someone brings up the ‘argument’ between the various ways to illustrate drag-loading (how increases in mass divide drag force) the side that argues against the existence of drag-loading (if that is done) can argue with the applet if they wish.
Just in case the above is aimed at me: my moderation on this forum does occur and I appreciate help as help materializes. If the above is considered to be help, by someone, then that someone is not on the same page as I am on. It is unlikely that this someone will ever be on the same page as I am on; however I’ve been wrong many times so that too can turn out to be an error.
Here again there exists an obvious lack of understanding. Crumpp has so far avoided filling in the blanks as requested and until such time as that is done the question as to whether or not Crumpp ignores drag loading remains to be seen. I wrote this: “Ignoring context, like ignoring the division of drag by weight, can lead to misrepresentations of the intended meaning. Why do that repeatedly, even after the problem is illustrated effectively?” That, out of context, concerned how Crumpp took a quote of mine out of context (where I used symbols to illustrate the concept of drag-loading) and rearranged the symbols to accomplish whatever Crumpp wished to accomplish and in that context Crumpp was suggesting that my quotes were an error of some sort without actually being specific as to the error requiring his schooling, therefore – the ignoring of context was ‘like’ ignoring the division of drag by weight. What exactly is the problem with the words I wrote? These: “Ignoring context, like ignoring the division of drag by weight, can lead to misrepresentations of the intended meaning. Why do that repeatedly, even after the problem is illustrated effectively?” If I intend to illustrate how drag-loading works, then I do that and I do so effectively if the person reading or viewing, or working (the applet) the illustration wants to play along. In context that effort can be likened to a vertical zoom climb in a few Fighter Planes going straight up from 1000 meters starting altitude at the top speed of the slowest plane compared, where the engine power is off to see which plane will force all the other planes higher like a slow race going straight up. Using the applet the person can see how the more massive plane will tend to go higher due to greater drag-loading. The P-47 versus the Spitfire involves a more massive plane with a larger size externally and therefore the larger size amounts to greater drag. The Fw190 is a smaller shape (and a more aerodynamically slippery one) than the Spitfire and the Fw190 is also more massive. Like this: Fw190 least drag and medium weight Spitfire medium drag and least weight P-47 most drag and most weight The P-47 is, PERHAPS, so much more massive that the higher drag is divided greatly by the much higher mass (weight) – it goes higher according to more than one source and those sources also add thrust like this: Fw190 least drag, medium thrust, medium mass Spitfire medium drag, least thrust, least mass P-47 most drag, most thrust, most mass If someone were to imagine that I am capable of thinking for myself (without all the help), then someone can avoid attributing my thoughts as they are spoken by the Straw-Man and his creators.
That, moderators, is a threat. Threats are either taken seriously or lightly. I prefer to take them seriously because someone capable of being so careless as to publish threats could be capable of just about anything. |
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Good question especially when the one who posts that weasels around when challenged on it.
Unpowered ballistics, the true approach to powered zoom climb!
Unpowered ballistics, the true approach.........
It's only ridiculous to try and reason with you. You have a whole barn full of straw. Unpowered straw for unpowered ballistics, the true approach to powered zoom climb.
Really? Drag, Weight, and what? The division relation is now a symbol?
That, moderators, is a Straw Man. "My views are solely my own and do not reflect the views of my Squad or its members" |
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Yes M_Gunz I explained the conditions of my analysis from the begining. Both sides are guilty of not listening to the other. All the best, Crumpp If I can't advertise for my Museum. Then there is no point in posting on these forums. |
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Well I do believe you were the one to introduce EAS and elaborate on it's virtues so I'm glad that the monologues you have had with yourself in the posts above have straightened out your understanding of how they relate to each other. As I said before, I do not care what method you use as long as it's clear what you do in your calculation. Currently it is not which bring us back to the questions I have now put to you three times and which you still have not answered: Are you saying that the calculation you made above does not represent flying conditions at 0 Km 400 Km/h TAS but actually represents flying conditions at 400 Km/h TAS at 7 Km and that you have used 215 KEAS (Knots equivalent airspeed?) in the equation above to achieve this? What Cdo and e (Oswald factor) do you assume for the Spitfire and Fw190 respectively? An alternative to disecting your method of calculation further would be if you could put this statement you made above into context: "Wow! No wonder you are up in arms. My analysis and conclusions is based on 400kph EAS and 600kph EAS at the BMW801's 1st Gear FTH." Does that mean that you now accept that the Spitfire Mk9 accelerates better than the Fw 190 A3 at 7 Km 400 Km/h TAS or do you prefer to dig deeper into the matter?  |
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This is a standard in aerodynamics Holtzauge. 
